ITPA and juvenile idiopathic arthritis: In our analysis (Pastore et al., 2014), the most common functional variants of ATIC, ITPA, and SLC19A1 were associated with clinical response to methotrexate evaluated as remission stable for a 6-months period, as ACRPed score and as change in Juvenile Arthritis Disease Score (JADAS) in 69 patients with JIA.